3D printer file type support
Blender supports the STL (STereoLithography) format which is supported by all printers and considered as standard for prototyping.

Shapeways for example supports the file types: STL, OBJ, X3D, Collada or VRML97/2.

Blender comes with support of STL, OBJ, X3D and Collada. 


Documentation on import formats
Documentation on export formats


When there is a public demand for a specific file format someone will create an import / export addon for it.